In terms of vocabulary, the vocabulary of band 6 is obviously more than that of band 4. Similarly, there will be some overlapping words in CET-4 and CET-6, so as long as you remember the words in CET-4 and CET-6 firmly, you only need to remember the words that are not in CET-4 and CET-6 when preparing for the exam.
Memorizing words is a long and boring process, and mastering methods can get twice the result with half the effort. I'll share with you two common methods.
1. Recite according to Ebbinghaus forgetting curve.
Ebbinghaus's law of forgetting, in human terms, means that what you just remember will soon be forgotten, and the longer it takes, the less you forget.
If you just recite a hundred words, you will soon forget 60 words after just 20 minutes, and the remaining 40 words will be forgotten gradually with the passage of time. If you remember 20 words after one month, these 20 words will be hard to forget all your life. Therefore, according to Ebbinghaus's forgetting curve, we should spread our time and review several times in a short time, instead of memorizing words in a whole block as everyone often does.
2. Words should be consolidated repeatedly.
I will have the habit of reciting texts in college, in fact, I am also reciting sentences in essence. Generally, when 1, the number of new words is the largest. After reciting the text, I probably remembered all the new words, but I will review them again in about three days. At this time, some words are new, but it doesn't matter. Just remember to mark it. If you consolidate it repeatedly, you can remember the words first, then.
Finally, I wish the exam success!